This invention generally relates to air cooled heat exchangers. More specifically, this invention relates to an improved method and structure for supporting fluid carrying tubes of air cooled heat exchangers which may be used for condensers or evaporators in refrigeration systems. Heat exchangers of the type contemplated by the present invention commonly include tube bundles with a relatively large number of thin walled copper parallel tubes connected in pairs at their ends by return bends to form a fluid circuit. Fins are secured generally transverse to the parallel tubes to enhance heat transfer. It is common in the prior art to provide a rigid connection between the tubes of the tube bundle and the supporting means at each end of the tubes.
For purposes of simplifying explanation, the following description pertains to an application where the heat exchanger is a condenser. In use, air is passed over the tubes of the air cooled condenser in order to lower the temperature of, and hence condense, a vaporous refrigerant fluid flowing through the tubes from a refrigerant compressor. During this cooling process the tube bundle is subject to vibrations caused by pulsations of the fluid flowing within the condenser, as well as outside disturbances. Furthermore, the tubes forming the tube bundle are subject to expansion and contraction due to changes in temperature during the heat exchange process. As a result of the vibrations and the temperature changes there is great stress placed upon the tubes at locations where they are rigidly attached, for example, between the end plates at each end of the tubes of the tube bundle. This stress often results in leakage at these points of contact. One possible solution to the problem was to use thicker wall copper tube. However, this undesirably increased weight and expense. Another possible solution was to use softer tube support materials to absorb movement due to vibration and expansion and contraction. This solution too was undesirable.
Accordingly, there is a need for an improved mounting means between the fluid carrying tubes and the end plates of an air cooled heat exchanger to eliminate the rigid contact between the fluid carrying tubes and the end plates in order to obviate heat exchanger leakage problems and to do so in a relatively simple, cost effective manner.